             {:produces ["application/json"],
              :responses {200 {:schema UserUsageResponse
                               :description "User's usage calculated."}
-                         401 {:description "Not authorized to read usage."}
-                         403 {:description "Invalid request format."}}
+                         400 {:description "Invalid request format."}
+                         401 {:description "Not authorized to read usage."}}
              :get {:summary "Query a user's current resource usage."
                    :parameters {:query-params UserUsageParams}
                    :handler (read-usage-handler conn is-authorized-fn)}}))

                   :responses {200 {:schema [InstanceResponse]
                                    :description "The job instances were returned."}
                               400 {:description "Non-UUID values were passed."}
                               403 {:description "The supplied UUIDs don't correspond to valid job instances."}}
                   :handler (read-instances-handler-multiple conn is-authorized-fn)}}))

        (c-api/context

                   :responses {200 {:schema [JobResponse]
                                    :description "The jobs were returned."}
                               400 {:description "Non-UUID values were passed."}
                               404 {:description "The supplied UUIDs don't correspond to valid jobs."}}
                   :handler (read-jobs-handler-multiple conn is-authorized-fn)}
             :post {:summary "Schedules one or more jobs."
                    :parameters {:body-params JobSubmissionRequest}
